What kind of trickery is this?

I want to learn herbalism so I can pick flowers and similar nice stuff. But I cannot train it from herbalism trainers, I figured it is because I have some other skills taking up place, so I wanted to unlearn them to get a new one. BUT, that option is not present. Is there a different approach to learning a new skill?
I need some plant ingreedients for some enchants, and I desire to pick them myself. I chose first aid and cooking just for no real reason. Buying food is so much easier and I don't care about cooking not even a tiny bit.
http://images.akamai.steamuserconten...422E140DE9F8E/

Herbalism is Main Profession, you can only replace it with Enchanting or Tailoring. Not Cooking/FA / Fishing. So in order to learn it, you have to drop either one of those two in "Professions" tab, not in Secondary.

Oh, ok then. Yeah I've looked here now http://wowwiki.wikia.com/wiki/Catego...ry_professions
Well I'm glad to know that all of those alternatives to cooking and first aid are equally underwhelming. :P It would be stupid to have something useless like cooking replace something decent like herbalism imo. XD Yet herbalism does not create anything new, just allows us to gather stuff from the world that I why I thought that it could not be a main profession.
Thanks.